You will need this licence if you intend to operate as or carry on a business as an unsupervised electrician undertaking electrical work. Electrical work includes electrical installation work, electrical fitting work and electrical equipment work.
This licence does not authorise you to act as an electrical contractor. If you are not employed by someone who holds an electrical contractor's licence or an in-house electrical installing work licence (e.g. you are a sole trader), then you will also need the appropriate one of those licences.